Tunneling machine guidance by impingement of laser beam on pair of machine carried targets



y 1967' T. N. WILLIAMSON ETAL 3,321,248

TUNNELING MACHINE GUIDANCE BY IMPINGEMENT OF LASER BEAM ON PAIR OF MACHINE CARRIED TARGETS Filed March 9, 1965 2 Sheets-Sheet 1 THOMAS N. WILLIAMSON JOHN M. MULLINS CALVIN D. SH OLTESS INVENTORS aaim zy ATTORNEY M y 1967 T. N. WILLIAMSON\ ETAL 3,321,243

TUNNELING MACHINE GUIDANCE BY IMPINGEMENT OF LASER BEAM ON PAIR OF MACHINE CARRIED TARGETS 2 Sheets-Sheet 2 Pi led March 9, 1965 THOMAS N. WILLIAMSON W JOHN M. MULLINS CALVIN D. SHOLTESS INVENTORS ATT RNEY United States Patent TUNNELING MACHINE GUIDANCE BY IMPINGE- MENT 0F LASER BEAM 0N PAIR OF MACHlNE CARRIED TARGETS Thomas N. Williamson and John M. Mullins, Houston, and Calvin D. Sholtess, Dallas, Tex., assignors to Hughes Tool Company, Houston, Tex., a corporation of Delaware Filed Mar. 9, 1965, Ser. No. 438,280 Claims. (Cl. 299-1) ABSTRACT OF THE DISCLOSURE A guidance system in which the pair of targets fixed on the tunneling machine are mounted parallel to and offset from the axis of the rotary drilling head of the machine. The images of the beam on the two targets are simultaneously visible to the operator, enabling him to detect all types of errors in machine orientationtwist, offset, skew and roll.

The complete system includes a telescope mounted with the laser beam projector as a unit. Typically, the optical axis of the telescope is made parallel to the beam axis and the unit is supported from the tunnel wall with the telescope trained on alignment markers to define the desired tunnel direction. The well known coherence of a laser beam makes it possible to mount the unit at a considerable distance from the tunneling machine.

This invention relates to the formation of a hole on a prescribed course through the earth and more particularly to an improved guidaince system for maintenance of predetermined drive direction of a tunneling machine.

Large tunnels are often dug in mountainous regions by a rotary drilling machine locked against the tunnel wall by a number of radially disposed hydraulic rams which center the machine and its drill stern on the longitudinal axis of the tunnel and, as the rotating drill head cuts away the earth, the head is pushed forward by the machine. At the end of each cutting stroke, the machine is advanced toward the projected head and reset for a succeeding cut.

Roll of the machine about its longitudinal axis is sometimes caused by the supporting rams slipping on the tunnel wall with torque reaction. Other displacements, such as angular inclination or lateral shift of the machine from its intended drilling direction, may result from a number of causes, including uneven hardness of tunnel wall surface, variations in load resistance in different zones of the tunnel face being penetrated, or operator error. Machine position displacement needs prompt correction and the machine operator must be constantly alert to change. Heretofore, course guidance was directed by a surveyor sighting from a rearward station or was controlled by the operator sighting back along a long and tensioned gauge wire strung longitudinally from the tunnel wall on the predetermined line of tunnel direction. Upon noting deviations, the operator effected relative adjustment of the hydraulic rams for repositioning the tunneling machine. It is an object of this invention to provide an improved tunnel machine guidance system for a more positive and reliable indication of cutting direction at all times, whereby cutting operations can be better controlled and kept on proper course by prompt realignment of the machine whenever position deviations develop.

3,321,248 Patented May 23, 1967 Another object is to provide a guidance system utilizing a laser device fixedly supported in trailing relation to a forwardly advancing boring machine to project a narrow beam forwardly on a line parallel with and radially spaced from the axis of the rotary cutting head and which beam is for reception by and impingement on a pair of machinecarried fore and aft targets whose comparative readings accurately signal machine position.

A further object of the invention is to provide an arrangement for presetting the fixed position of the beam projector by sighting on a properly located reference marker and through a rearwardly directed scope on an axis in predetermined relation with the axis of the projected beam.

A still further object of the invention is to provide for projecting a signal beam on a plate target protectively surrounded within a dirt shield with which there preferably is associated an arrangement to direct clean air under pressure both to sweep dust from the face of the plate and to blow outwardly from the shield and thereby resist entry of tunnel dust.

Additional objects and advantages will become apparent upon reference to the accompanying drawings, wherein:

FIG. 1 is a somewhat schematic view illustrating the application of the guidance system to a tunnelling machine in operative relation within the earth;

FIG. 2 is a view similar to FIG. 1 on a larger scale, and shows an alternate alignment marker;

FIG. 3 is a horizontal section on line 3-3 of FIG. 2',

FIG. 4 is an end section of a fragment of a tunnel bore showing the mounting therein of a telescope-laser unit;

FIG. 5 is a vertical section of a target unit, and

FIG. 6 is an elevation of the target unit with a portion in section.

Application of the invention to various conventional excavators and other equipment is contemplated. For illustration, the tunnelling machine 10 in FIG. 1 includes a rotatable drilling head 11 mounting any suitable kind of bit or cutters for working on the face of the earth to be excavated. The drill head 11 is carried on the front end of a longitudinally shiftable drive shaft 12 having bearing support within a cylindrical housing 13 which encloses power transmission mechanism. Axially spaced apart sets of two or more hydraulic rams 14-14 project radially from the cylindrical housing 13 and terminate in arcuate pads for seating against the tunnel wall and positioning the machine centrally of the tunnel. Such seating engagement also is a friction brake to resist drive torque reaction.

The power transmission mechanism in response to actuation of manual controls at an operators station or console (not shown) located on one side of the machine comprises, by way of example, electric motor drive equipment for rotating the drilling head 11 about the longitudinal center line of the machine and for operating hydraulic pumps for the application of substantially constant forward thrust on the drill head during drilling. The hydraulic power is also for actuation of the locating rams 14 and for advancing the machine to the extended drill head at the end of its forward stroke in preparation for a repositioning of the machine. Machine location relative to the desired course and grade of the tunnel is dependent on relative length settings of the several rams and proper control of such settings enables maintenance of, and corrections in, positions both initially as well as during drilling operations without interruption of the drilling opera tion.

To provide the operator with easy and continuous readings of machine positions, in one preferred embodiment of the invention there are mounted on the machine in radially spaced relation with its center line, a pair of axially spaced apart targets 15 and 16 for comparative observation of light spots on target regions and which spots result from impingement on the target faces of a narrow light beam projected forwardly on a path parallel with the desired axial direction of the tunnel. Ideally, the light beam projector is a gas laser 17, such as Perkin-Elmer Model 5200, which is capable of generating a coherent beam of small diameter on the order of onefourth to one-half of an inch for an effective range of several hundred feet with a small divergence.

Each target, as best seen in FIGS. and 6, consists of a plate or disc 18 of either transparent or translucent material such as ground or frosted glass or plastic, preferably having measurement lines; for example, grid marks etched therein and being mounted within a hood or tubular housing 19. The housing 19 has a mounting bracket 20 to be bolted on the outside of the machine with or without intervening spacer shims for enabling adjustment as needed. In the case of the rearward target 15, there are placed adjacent the front and rear faces of the target plate 18 a pair of circular tubes 21, each having a succession of small jetting ports or nozzles directed toward its adjacent plate face and also having a pipe coupling with a manifold 22 (see FIG. 1) leading from a suitable source of filtered air such as a compressor indicated at 23. The air, after being filtered at the intake to the compressor, is jetted under pressure across the opposite faces of the target plate 18 and exhausts through the front and rear openings of the tubular housing 19 whereby to rid the same of dirt and dust which is frequently quite heavy in the area of a tunnelling machine. It may be pointed out here that while the foremost target 16 may be identical in structure to the rearmost target 15, it can also be simplified by using a perforated air jetting ring at only the rear face of the target plate. The laser beam will strike and present a signal image on the plate 18 of the rearward target and pass on to and impinge on the plate of the forward target 16 as a second readable signal.

The previously referred to adjustable mounting contemplates either a hinge or a slide connection for the rearward target 15 to enable the target to be shifted out of the beam path for unimpeded beam passage to the forward target 16. This arrangement will insure selective and independent readings on either target plate of similarly pronounced images. Optionally, both longitudinally spaced apart target plates may be shielded within an elongated tubular housing whose length can be extended to terminate rearwardly beyond the zone of high dust concentration. A transparent closure for the tube end will exclude dust and pass the beam and other transparent closures over windows adjacent both targets and will permit image observation. Conveniently, such closures can be cleaned if needed by jetting pressure air thereon or by mechanical wipers.

Identical beam image positions centered on both targets will indicate that the machine is on course. Should beam positions on both targets be offset from center within the same circumferential direction about the machine longitudinal axis, the operator will know to check for roll of the machine and correct if necessary. In the absence of roll, any relative displacements of the beam image from target centers represents actual deviation from course. For some installations, use is contemplated of a television camera for reading beam images and transmitting the readings to a viewer in the operators station.

For presetting laser position, the laser, as here shown, is secured as one component of an assembly unit having as another component a transit telescope 24 in closely spaced parallel relation with the laser, and the assembly also includes an adjustable mounting by which the lasertelescope unit can be shifted to a setting as influenced by training the scope rearwardly toward a suitable reference point or alignment marker means. The problems here concerned will be made clearer by mention of exemplary work conditions. Thus, when a tunnel is drilled to seventytwo inches or larger diameter, the working distance between the target and the laser can range between ten feet and several hundred feet, while the distance between the telescope and the reference point or points can be over an even greater range.

As seen in FIG. 1, accuracy is attainable by hanging two plumb lines 2525 from stationary positioning means or holder spads preset in the tunnel wall in predetermined course alignment and at points spaced from one another approximately one hundred feet. Such plumb lines give a vertical plane reference. Beyond the farther plumb line there can be set up a vertical scale or levelling rod 26 for cooperation with the telescope in presetting course direction with reference to the horizontal.

The arrangement of FIG. 2 differs from FIG. 1 in that one plumb line 25a is disposed rearwardly of the telescope-laser unit and a second plumb line 25a hangs from directly above and in locating cooperation with a centering mark or point 25b carried by and on the vertical center line of the telescoping-laser unit. This forward plumb line 25a will have a pre-established location on the tunnel course and the height of its bob will be preset to proper grade. After the telescope-laser unit has been mounted below and has been adjustably positioned to present the centering mark 25b in proper height and vertical alignment with the forward plumb bob and line 25a, the vertical cross hair of the transit will be lined up on the rearward plumb line, usually the one installed at the previous station. If a change in either course or grade is called for at this stage of tunnelling, suitable adjustment can be made on appropriate horizontal and vertical transit scales. Following each advance of the machine, either to the range limit of the laser or to a distance at which a course or grade change has been specified, the transit will be turned about its vertical axis through a specified angle such as when the course is to remain unchanged, to enable a forward sighting for locating a plumb line 25a at a new advance station. The transitlaser unit is then brought forward and set up at the new station in accordance with the precedure previously described.

The rearwardly directed telescope 24 and the forwardly directed laser 17 are bound together by encircling straps as at 27 so that the axis of the laser is parallel with the optical axis of the telescope and the combined unit, like the usual surveyor transit, has a transverse pivotal axis with the vertical circle 28 and two threaded adjusters for fine alignment in horizontal and vertical planes. In addition, a supporting pedestal for the laser-telescope unit includes a horizontal adjuster 29, a vertical adjuster 30, a swivel connection 31 and a rack and pinion jack 32 for set up adjustment. A base flange 33 on the pedestal column contains diametrically opposite parallel elongated slots 34-34 to receive fastening bolts 35, each extending through a transverse slot 36 in a platform 37. The cooperating slots accommodate lateral adjustment of the pedestal toward vertical plane alignment setting whereupon the bolts are drawn tight. The platform 37 has dependent convergent legs 38 and, as illustrated in FIG. 4, the platform unit is rock bolted to one wall of the tunnel so as to be centrally offset with generous passage clearance above the floor of the tunnel for personnel and equipment, including mine cars and conveyors for carrying out excavated material.

Upon energization of the laser, its light beam is projected forward and coincides with or defines the course and the grade to be followed. On-target images of the signal beam are indicative of machine positions and the hydraulic rams 14 of the two sets can be individually shortened or lengthened as needed to shift the machine for centering the targets in relation to the light beam. When both targets are centered, the machine longitudinal center line is parallel or coaxial with the desired drilling direction. Any subsequent displacement of the beam image from target center indicates deviation from the selected course. As the drilling operation proceeds, continuous comparison of relative off-center images in any quadrant of the two targets affords ready observance of a deviation and the relative lengths of the several rams 14 can be promptly readjusted for steering the tunnel cutting operation on course. Roll displacement about the longitudinal axis of the machine will also be made known and enable proper steps to be taken in restoring machine attitude. Identical off-center beam image positions on both targets correspond with the extent that the machine center line is in parallel misalignment with the course. If the beam image is in other than identical positions on the two targets, the machine center line is out of parallel with or inclined from the given course. When the boring operation has progressed to the forward limit of the drill head stroke, the machine again is advanced bodily and reset to laser beam alignment. With an effective laser beam range greater than the distance to which the cutter head can be projected, laser setting need not be disturbed with each advance of the machine. Upon machine advance toward the limit of the beam range, the telescope-laser instrument will be moved forward to a new position adjacent the machine. In the manner previously described, the tunnelling machine can again go forward under proper guidance.

The guidance system as herein disclosed will find uses for travel guidance of other than tunnel equipment. For some work it will be feasible to mount the laser on the machine so as to direct its beam toward either a forwardly or a rearwardly spaced target and on an established line and grade setting.

While the foregoing sepcification has detailed only a preferred embodiment of the invention, it is to be understood that various modifications and rearrangements may be made as come within the scope of the appended claims.

What is claimed is:

1. In a guidance system for a machine whose work travel direction is to be controlled, a pair of targets arranged to be carried by the machine in spaced apart alignment with one another on an axis parallel with the line of machine working travel, a signal directing device located rearwardly of the targets and arranged to project a target impinging signal beam on a forward line and of a transverse dimension which is smaller than the target area exposed thereto, preset alignment marker means fixed in rearwardly spaced relation with said machine and a direction-setting member fixedly secured with the signal directing device as a unit therewith for alignment co-action with the alignment marker means so as to aim the beam projection path of said device in selected relation with the alignment marker means for the indication by comparative locations of beam impingement on the two targets of machine position relative to said alignment marker means.

2. In a guidance system as in claim 1, an adjustable mounting for said unit enabling the unit to be shifted into position in which the direction-setting member is focused on the alignment marker means.

3. In a guidance system for a tunnelling machine, alignment marker means preset rearwardly of the machine in longitudinally spaced relation therewith and in longitudinal alignment with the given tunnelling direction, a beam projecting device located fonwardly of the alignment marker means, an adjustable mounting positioning said device for forward projection of its beam, a marker sighting member fixed with said device for sighting rearwardly on said marker means and shiftable upon adjustment of said mounting into longitudinal sighting alignment with the marker means for thereby setting the path of beam projection from said device to that of given tunnelling direction, a pair of longitudinally spaced targets mounted on the machine in axial alignment with the beam path when the tunnelling machine is in a predetermined operating positionv whereby machine position displacement is indicated by displacement of the target means in relation to the axis of said beam.

4. In a guidance system for a tunnelling machine, a first pair of cooperating components comprising a signal beam projector and pair of axially spaced targets for alignment with the beam axis, a second pair of cooperating components comprising a viewing scope and an alignment marker with which the scope is to be aligned, means joining the scope and the projector as a unit, mounting means positioning said unit rearwardly spaced from said targets, other mounting means positioning the targets on the machine, additional mounting means positioning said alignment marker rearwardly spaced from the tunneling machine, at least one of said mounting means being adjustable for setting said components in operating relation in which the projector and the targets are initially in 1ongitudinal alignment with one another and the scope and the marker are in longitudinal alignment with one another.

5. In a guidance system for a tunnelling machine, direction alignment marker means having a preset position rearwardly spaced from the tunnelling machine and fixed in relation to a predetermined course to be tunnelled, a rearwardly directed sighting scope to be focused on said direction alignment marker means, a support movably mounting the sighting scope for adjustment thereof to set the scope in sighting alignment longitudinally with the marker means, a signal beam projector fixed relative to the sighting scope and arranged to project a signal beam forwardly without appreciable beam spread and a pair of targets in longitudinally spaced apart relation on the machine and operatively positioned to be in the path of signal beam projection for a comparative reading of beam reception by the two targets as an indication of machine tunnelling direction.

6. In a guidance system as in claim 5, wherein said signal beam projector comprises a laser device to project on the target area a relatively narrow output light beam.

7. In a guidance system as in claim 5, together with means adjustably positioning said targets relative one to the other and accommodating displacement from the projected beam of that target which is closer to the projector.

8. The method for maintaining a tunnelling machine on a prescribed course comprising presetting the location of marker means to coincide with a prescribed direction training the telescope of a combined telescope and beam projector unit toward the marker means, adjusting the position of the unit into alignment with the marker means as the latter is viewed by the telescope, then observing on a pair of longitudinally spaced apart and machinecarried targets, the beam images thereon as projected by the projector, adjusting machine position until beam images are centered on both targets, then operating the tunnelling machine while comparing beam images on the targets for determining machine positioning readjustments needed to steer the machine in the prescribed direction.

9. The method for maintaining a tunnelling machine on a predetermined direction of travel comprising prepositioning a beam projector for emission of its beam on an axis parallel with the predetermined direction of the tunnel, initially adjusting the position of a tunnelling machine to center a pair of axially spaced apart targets in coaxial alignment with the beam, maintaining Watch of comparative beam images on the two targets during tunnel machine operation for indications of off-center machine displacements and readjusting machine position as needed to restore the position of the machine on its intended direction.

10. In a guidance system of the character described,

machine means to be maintained on a predetermined longitudinal direction of travel, stationary positioning means spaced longitudinally from the machine means, a telescope and a beam projector arranged on parallel axes Within the space between the machine means and said positioning means and oppositely disposed with reference to the viewing direction of the telescope and the beam projecting direction of the projector, a pair of longitudinally spaced apart beam-receiving targets fixed on one of the aforesaid means, marker equipment fixedly attached to the other of the aforesaid means and an adjustable mounting of the telescope and the projector accommodating their adjustment as a unit into a setting in which the axis of the telescope aligns longitudinally with the marker equipment and the axis of the beam projector aligns with the targets and presents centered images on both targets References Cited by the Examiner UNITED STATES PATENTS 1,602,698 10/1926 Nielson 3346.2 2,198,836 4/1940 Patton 33-462 2,376,700 5/1945 Kinney 33-46.2 2,666,631 1/1954 Mavor 299-1 2,761,666 9/1956 Heimaster et al. 299-l 3,069,983 12/1962 Pizzarotti et al. 94-46 FOREIGN PATENTS 549,769 5/1932 Germany.

ERNEST R. PURSER, Primary Examiner. 

1. IN A GUIDANCE SYSTEM FOR A MACHINE WHOSE WORK TRAVEL DIRECTION IS TO BE CONTROLLED, A PAIR OF TARGETS ARRANGED TO BE CARRIED BY THE MACHINE IN SPACED APART ALIGNMENT WITH ONE ANOTHER ON AN AXIS PARALLEL WITH THE LINE OF MACHINE WORKING TRAVEL, A SIGNAL DIRECTING DEVICE LOCATED REARWARDLY OF THE TARGETS AND ARRANGED TO PROJECT A TARGET IMPINGING SIGNAL BEAM ON A FORWARD LINE AND OF A TRANSVERSE DIMENSION WHICH IS SMALLER THAN THE TARGET AREA EXPOSED THERETO, PRESET ALIGNMENT MARKER MEANS FIXED IN REARWARDLY SPACED RELATION WITH SAID MACHINE AND A DIRECTION-SETTING MEMBER FIXEDLY SECURED WITH THE SIGNAL DIRECTING DEVICE AS A UNIT THEREWITH FOR ALIGNMENT CO-ACTION WITH THE ALIGNMENT MARKER MEANS SO AS TO AIM THE BEAM PROJECTION PATH OF SAID DEVICE IN SELECTED RELATION WITH THE ALIGNMENT MARKER MEANS FOR THE INDICATION BY COMPARATIVE LOCATIONS OF BEAM IMPINGEMENT ON THE TWO TARGETS OF MACHINE POSITION RELATIVE TO SAID ALIGNMENT MARKER MEANS.
 8. THE METHOD FOR MAINTAINING A TUNNELLING MACHINE ON A PRESCRIBED COURSE COMPRISING PRESETTING THE LOCATION OF MARKER MEANS TO COINCIDE WITH A PRESCRIBED DIRECTION TRAINING THE TELESCOPE OF A COMBINED TELESCOPE AND BEAM PROJECTOR UNIT TOWARD THE MARKER MEANS, ADJUSTING THE POSITION OF THE UNIT INTO ALIGNMENT WITH THE MARKER MEANS AS THE LATTER IS VIEWED BY THE TELESCOPE, THEN OBSERVING ON A PAIR OF LONGITUDINALLY SPACED APART AND MACHINECARRIED TARGETS, THE BEAM IMAGES THEREON AS PROJECTED BY THE PROJECTOR, ADJUSTING MACHINE POSITION UNTIL BEAM IMAGES ARE CENTERED ON BOTH TARGETS, THEN OPERATING THE TUNNELLING MACHINE WHILE COMPARING BEAM IMAGES ON THE TARGETS FOR DETERMINING MACHINE POSITIONING READJUSTMENTS NEEDED TO STEER THE MACHINE IN THE PRESCRIBED DIRECTION. 